WO2021185027A1

WO2021185027A1 - Slip ring unit and electric machine

Info

Publication number: WO2021185027A1
Application number: PCT/CN2021/077272
Authority: WO
Inventors: Danyang HAN; Xing Zhang; Yang Xu
Original assignee: Abb Schweiz Ag
Priority date: 2020-03-17
Filing date: 2021-02-22
Publication date: 2021-09-23
Also published as: CN111245160A

Abstract

Embodiments of the present disclosure relate to a slip ring unit and an electric machine. The slip ring unit comprises: a slip ring box comprising a gas inlet and a gas outlet; a slip ring body disposed in the slip ring box; a slip ring brush disposed in the slip ring box and being in contact with the slip ring body; and a suction device disposed at the gas outlet and configured to draw gas in the slip ring box via the gas outlet, such that cooling gas enters the slip ring box via the gas inlet. In accordance with the embodiments of the present disclosure, the slip ring brush and the slip ring body are cooled by suction, such that the cooling effects on the slip ring brush and the slip ring body can be enhanced and the powder produced in the slip ring box can be easily collected and cleaned.

Description

SLIP RING UNIT AND ELECTRIC MACHINE

FIELD

Embodiments of the present disclosure generally relate to the field of slip rings, and more specifically, to a slip ring unit and an electric machine comprising a slip ring.

BACKGROUND

Slip ring unit is a rotary connector for use in an electric machine (electromotor or electric generator) to carry out signal and electric power transmissions between two relatively rotating mechanisms. The slip ring unit can implement a sliding electric contact through a sliding friction between a carbon brush of the stator and the slip ring body of the rotor.

There are currently a variety of types of slip ring units, such as co-axial fan slip ring unit, auxiliary fan slip ring unit and the like. The co-axial fan slip ring unit is extensively used as it is more economical and easy-to-assemble than other types. In the co-axial fan slip ring unit, a fan mounted on the same rotary shaft with the slip ring body is often used to blow the cooling air into the slip ring box to cool down the carbon brush and the slip ring body. However, the fan and the rotary shaft are heated by the electric machine during the operation of the electric machine, therefore, the temperature of the fan and the rotary shaft is higher than the temperature of the cooling air to be blown. In such ventilation structure, the cooling air will be heated by the fan and the rotary shaft at first and then blown into the slip ring box. Therefore, the cooling air entering the slip ring box has an increased temperature, which may compromise the cooling effects on the carbon brush and the slip ring body. In addition, the friction between the carbon brush and the slip ring body produces carbon powder during the operation of the electric machine. When the cooling air is blown by the fan into the slip ring box to cool down the carbon brush and the slip ring body, the carbon powder is also blown away by the air and could hardly be collected and cleaned.

Hence, a slip ring unit which cools the carbon brush and the slip ring body more efficiently and enables better collection of the carbon powder is required.

SUMMARY

An object of the present disclosure is to provide a slip ring unit and an electric machine comprising a slip ring, to at least partially solve the above problems in the prior art.

In accordance with a first aspect of the present disclosure, a slip ring unit is provided. The slip ring unit comprises: a slip ring box comprising a gas inlet and a gas outlet; a slip ring body disposed in the slip ring box; a slip ring brush disposed in the slip ring box and being in contact with the slip ring body; and a suction device disposed at the gas outlet and configured to draw gas in the slip ring box via the gas outlet, such that cooling gas enters the slip ring box via the gas inlet.

In the embodiments of the present disclosure, the gas in the slip ring box is drawn by the suction device provided at the gas outlet, such that the cooling gas enters the slip ring box through the gas inlet and a gas flow path from the gas inlet to the gas outlet is formed in the slip ring box to cool down the slip ring brush and the slip ring body. Compared with the traditional blow-cooling method, the suction approach avoids heating the cooling gas before it enters the slip ring box to more efficiently cool down the slip ring brush and the slip ring body. Moreover, because the suction device is disposed at the end of the gas flow path, it can draw the powder resulted from the friction between the slip ring brush and the slip ring body out of the slip ring box. Therefore, the powder in the slip ring box would not be blown away as it does in the traditional blow-cooling method and can be easily collected and cleaned.

In some embodiments, the suction device includes: a fan configured to draw gas in the slip ring box when rotating; and a cover covering the fan and the gas outlet and comprising an exhaust port for discharging gas drawn from the slip ring box by the fan to an external environment. In these embodiments, the gas in the slip ring box is drawn by the fan, such that the cooling gas enters the slip ring box via the gas inlet without being heated, so as to more efficiently cool down the slip ring brush and the slip ring body. In addition, the powder produced in the slip ring box, instead of being blown away, can be reliably drawn out of the slip ring box, since the fan is disposed at the end of the gas flow path. Furthermore, the powder can be easily collected at the exhaust port of the fan cover.

In some embodiments, the fan and the slip ring body are mounted on a same rotary shaft. In such embodiments, the fan and the slip ring body are co-axially mounted for an economical, easy-to-assemble and space-saving slip ring unit.

In some embodiments, the slip ring unit further comprises: a baffle disposed in the slip ring box between the gas inlet and the slip ring brush, wherein a predetermined space in communication with the gas inlet is formed between the baffle and an inner wall of the slip ring box, and the baffle is provided thereon with a plurality of openings facing towards the slip ring brush. In these embodiments, the gas flow path in the slip ring box is adjusted with the baffle, such that the cooling gas entering the predetermined space can flow through the openings on the baffle towards the slip ring brush and the slip ring body. As a result, the cooling effects on the slip ring brush and the slip ring body are enhanced and the individual slip ring brushes are also cooled more uniformly.

In some embodiments, a gas guide is disposed at an edge of at least one opening of the plurality of openings, the gas guide being configured to guide the cooling gas towards the slip ring brush. In these embodiments, the gas guide disposed at the edge of the openings can further define the gas flow path in the slip ring box. Therefore, the cooling gas is basically guided towards the slip ring brush and the slip ring body to further enhance the cooling effects on them.

In some embodiments, the gas guide is disposed at a position on an edge of the at least one opening close to the suction device and is tilted towards a direction away from the suction device with respect to the baffle. In these embodiments, the gas guide is disposed at a position on the edge of the opening close to the suction device in view of the position of the suction device, such that the cooling gas is guided to tilt towards a direction away from the suction device. In addition to preventing certain gas flow from directly flowing towards the gas outlet after passing the openings on the baffle, the above arrangement guides basically all cooling gas to the slip ring brush and the slip ring body. As a result, an optimal cooling effect can be achieved.

In some embodiments, each of the plurality of openings is rectangular and the gas guide tilting towards an interior of each opening is disposed at two adjacent sides of each opening close to the suction device. In these embodiments, the cooling gas is guided by the plurality of rectangular openings on the baffle and the correspondingly disposed gas guides to deliver a more uniform cooling effect on the individual slip ring brushes. Moreover, the gas guide arranged at two adjacent sides of the opening close to the suction device can reliably guide the cooling gas to the corresponding slip ring brush.

In some embodiments, the slip ring unit further comprises at least one partition plate for partitioning the predetermined space into a plurality of regions. In these embodiments, the gas flow distribution within the predetermined space is adjusted by the partition plate.

In some embodiments, the slip ring brush is a carbon brush.

In accordance with a second aspect of the present disclosure, an electric machine comprising a slip ring unit according to the first aspect is provided. In the embodiments of the present disclosure, the electric machine may be electromotor or electric generator. As the electric machine in accordance with the embodiments of the present disclosure includes the above described slip ring unit, it can provide the same advantages like the slip ring unit.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the following detailed description with reference to the accompanying drawings, the above and other objectives, features, and advantages of embodiments of the present disclosure will become more apparent. Several embodiments of the present disclosure will be illustrated by way of example but not limitation in the drawings, in which:

Fig. 1 illustrates a structure diagram of a slip ring unit in accordance with one embodiment of the present disclosure;

Fig. 2 illustrates a structure diagram of a baffle in accordance with one embodiment of the present disclosure;

Fig. 3 illustrates a front view of the baffle in Fig. 2;

Fig. 4 illustrates a top view of the baffle in Fig. 2; and

Fig. 5 illustrates a structure diagram of a baffle in accordance with a further embodiment of the present disclosure.

Throughout the drawings, same or corresponding reference numbers represent same or corresponding parts.

DETAILED DESCRIPTION OF EMBODIMENTS

The preferred embodiments of the present disclosure will be described in more details with reference to the drawings. Although the drawings illustrate the preferred embodiments of the present disclosure, it should be appreciated that the present disclosure can be implemented in various manners and should not be limited to the embodiments explained herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art.

As used herein, the term “include” and its variants are to be read as open-ended terms that mean “includes, but is not limited to. ” The term “or” is to be read as “and/or” unless the context clearly indicates otherwise. The term “based on” is to be read as “based at least in part on. ” The terms “one example embodiment” and “one embodiment” are to be read as “at least one example embodiment. ” The term “afurther embodiment” is to be read as “at least a further embodiment. ” The terms “first” , “second” and so on can refer to same of different objects.

As described above, the cooling is performed by blow in a conventional slip ring unit. In such case, the cooling air will be heated by a fan and its rotary shaft at first and then blown into a slip ring box. Accordingly, the temperature of the cooling air entering the slip ring box rises, which compromises the cooling effects on carbon brushes and the slip ring body. By contrast, the slip ring unit in accordance with embodiments of the present disclosure cools the electric brush and the slip ring body by suction, to avoid heating the cooling air before it enters the slip ring box. Therefore, the electric brush and the slip ring body can be more efficiently cooled down and the powder produced in the slip ring box can be easily collected and cleaned. Principles of the present disclosure are described below with reference to the drawings and the example embodiments.

Fig. 1 illustrates a structure diagram of a slip ring unit 100 in accordance with one embodiment of the present disclosure. As shown in Fig. 1, the slip ring unit 100 described here generally includes a slip ring box 2, a slip ring body 3, a slip ring brush 4 and a suction device 5. The slip ring box 2 has an interior space for receiving components and includes a gas inlet 21 and a gas outlet 22. Gas for cooling internal components may enter the interior space of the slip ring box 2 via the gas inlet 21 and exit from the interior space of the slip ring box 2 via the gas outlet 22. In the embodiments of the present disclosure, the cooling gas may be air or other available gases.

In one embodiment, the slip ring body 3 and the slip ring brush 4 are disposed in the interior space of the slip ring box 2 and are in contact with each other, as shown in Fig. 1. The slip ring body 3 may be arranged on the rotary shaft 6 to rotate under the drive of the rotary shaft 6, while the slip ring brush 4 is fixed in the slip ring box 2. During the operation of the slip ring unit 100, a sliding electric contact is implemented by a sliding friction between the slip ring brush 4 and the slip ring body 3. In the embodiments of the present disclosure, the slip ring body 3 and the slip ring brush 4 may be arranged in various known arrangements and their detailed working principles are not repeated here. Additionally, the slip ring body 3 and the slip ring brush 4 may also be arranged in other arrangements available in the future and the scope of the present disclosure is not restricted in this regard.

In some embodiments, the slip ring brush 4 may be a carbon brush. However, it should be understood that the above example is not intended to limit the scope of the present disclosure and those skilled in the art may use other available slip ring brush 4.

The suction device 5 provided at the gas outlet 22 is capable of drawing the gas in the slip ring box 2 via the gas outlet 22, such that the cooling gas enters the slip ring box 2 through the gas inlet 21 and a gas flow path from the gas inlet 21 to the gas outlet 22, as indicated by the arrows, is formed in the slip ring box 2 to cool down the slip ring brush 4 and the slip ring body 3. Compared with the traditional blow-cooling method, this suction approach avoids heating the cooling gas before it enters the slip ring box 2 via the gas inlet 21, which enables a more efficient cooling of the slip ring brush 4 and the slip ring body 3. Moreover, because the suction device 5 is disposed at the end of the gas flow path, it can draw the powder resulted from the friction between the slip ring brush 4 and the slip ring body 3 out of the slip ring box 2. Therefore, the powder in the slip ring box 2 would not be blown away as it does in the traditional blow-cooling method and can be easily collected and cleaned.

In some embodiments, the suction device 5 as illustrated in Fig. 1 includes a fan 51 and a cover 52. The fan 51 can draw the gas in the slip ring box 2 when rotating. The cover 52 covers the fan 51 and the gas outlet 22 and has an exhaust port 53 for discharging the gas drawn from the slip ring box 2 by the fan 51 to the external environment. Through the above arrangement, the gas in the slip ring box 2 is drawn via the gas outlet 22 and discharged to the external environment via the exhaust port 53 of the cover 52 when the fan 51 is rotating. Meanwhile, the cooling gas in the external environment may be sucked into the slip ring box 2 via the gas inlet 21 to cool down the slip ring brush 4 and the slip ring body 3. In addition, the powder produced in the slip ring box 2, instead of being blown away, can be reliably drawn out of the slip ring box 2, since the fan 51 is disposed at the end of the gas flow path. Furthermore, the powder can be easily collected at the exhaust port 53 of the fan cover 52.

In some embodiments, the fan 51 and the slip ring body 3 are mounted on a same rotary shaft 6, as shown in Fig. 1. During the operation of the slip ring unit 100, the rotary shaft 6 can drive the slip ring body 3 and the fan 51 to rotate together, to form a gas flow path of the cooling gas in the slip ring box 2 by suction of the fan 51. In such embodiments, the fan 51 and the slip ring body 3 are co-axially mounted for an economical, easy-to-assemble and space-saving slip ring unit 100. In other embodiments, the fan 51 may be arranged separately, rather than directly on the rotary shaft 6.

It should be appreciated that the suction device 5 may be disposed at the gas outlet 22 of the slip ring box 2 in any forms of structure as long as it can draw the gas out of the slip ring box 2 to form a gas flow path of the cooling gas in the slip ring box 2. For example, the suction device 5 may include more fans or other types of suction elements besides the fan. These alternative arrangements are also protected by the present disclosure.

In some embodiments, the slip ring unit 100 also includes a baffle 7 arranged in the slip ring box 2 between the gas inlet 21 and the slip ring brush 4, as shown in Fig. 1. A predetermined space 8 in communication with the gas inlet 21 is formed between the baffle 7 and an inner wall of the slip ring box 2. The baffle 7 is provided thereon with a plurality of openings (which are not shown in Fig. 1, but elaborated below with reference to Figs. 2-5) facing the slip ring brush 4. During the operation of the slip ring unit 100, the cooling gas firstly enters the space 8 after passing the gas inlet 2. The cooling gas in the space 8 may flow through the openings on the baffle 7 towards the slip ring brush 4 and the slip ring body 3 to cool them. In these embodiments, the gas flow path in the slip ring box 2 is adjusted by the baffle 7, such that the cooling effects on the slip ring brush 4 and the slip ring body 3 are enhanced and the individual slip ring brushes 4 are also cooled more uniformly.

Fig. 2 illustrates a structure diagram of the baffle 7 in accordance with one embodiment of the present disclosure; Fig. 3 illustrates a front view of the baffle 7 shown in Fig. 2; and Fig. 4 illustrates a top view of the baffle 7 shown in Fig. 2. According to Figs. 2 to 4, the baffle 7 may include a bottom plate 70 and two side plates disposed at two opposing sides of the bottom plate 70. The bottom plate 70 and the two side plates 73 enclose the predetermined space 8 shown in Fig. 1 together with the inner wall of the slip ring box 2. The bottom plate 70 is provided thereon with a plurality of openings 71. With reference to Figs. 1 to 4, the cooling gas firstly enters the space 8 after passing the gas inlet 21 during the operation of the slip ring unit 100. Afterwards, the cooling gas in the space 8 may flow through the openings 71 on the bottom plate 70 towards the slip ring brush 4 and the slip ring body 3 to cool them.

In some embodiments, a gas guide 72 is disposed at an edge 710 of each opening, as shown in Figs. 2 to 4. The gas guide 72 is provided to guide the cooling gas towards the slip ring brush 4. In these embodiments, the gas guide 72 disposed at the edge 710 of the openings 71 can further restrict the gas flow path in the slip ring box 2. Therefore, the cooling gas is basically guided towards the slip ring brush 4 and the slip ring body 3 to further enhance the cooling effects on them.

In some embodiments, with reference to Figs. 1 to 4, the gas guide 72 is disposed at a position on the edge 710 of the opening 71 close to the suction device 5 and is tilted towards a direction away from the suction device 5 with respect to the baffle 7. In these embodiments, the gas guide 72 is disposed at a position on the edge 710 of the opening 71 close to the suction device 5 in view of the position of the suction device 5, such that the cooling gas is guided to tilt towards a direction away from the suction device 5. In addition to preventing certain gas flow from directly flowing towards the gas outlet 22 after passing the openings 71 on the bottom plate 70, the above arrangement guides basically all cooling gas to the slip ring brush 4 and the slip ring body 3. As a result, an optimal cooling effect can be achieved.

In some embodiments, each opening 71 is rectangular and the gas guides 72 tilting towards the interior of the opening are disposed at two adjacent sides of each opening 71 close to the suction device 5, as shown in Figs. 2 to 4. For example, the bottom plate 70 may be provided thereon with three pairs of openings 71, wherein each pair of openings 71 is disposed corresponding to one slip ring brush 4 and the gas guides 72 tilting towards the interior of the opening are disposed at one side of each pair of openings 71 close to the suction device 5 and a side adjacent thereto. In these embodiments, the cooling gas is guided by the rectangular opening 71 on the baffle 7 and the correspondingly disposed gas guides 72, so as to deliver a more uniform cooling effect on the individual slip ring brushes 4. Moreover, the gas guides 72 arranged at two adjacent sides of the opening 71 close to the suction device 5 can reliably guide the cooling gas to the corresponding slip ring brush 4.

In the embodiments of the present disclosure, the bottom plate 70 may be provided thereon with any numbers of openings 71 and the scope of the present disclosure is not restricted in this regard. In accordance with the embodiments of the present disclosure, the openings 71 on the bottom plate 70 may be arranged randomly and the scope of the present disclosure is not restricted in this regard. In the embodiments of the present disclosure, the individual openings 71 may have other shapes, such as oval and diamond etc., and the scope of the present disclosure is not restricted in this regard. In the embodiments of the present disclosure, the gas guide 72 may be disposed at the edge of all or part of the openings 71 and the scope of the present disclosure is not restricted in this regard.

Fig. 5 illustrates a structure diagram of the baffle 7 in accordance with a further embodiment of the present disclosure. The baffle 7 in Fig. 5 has a similar structure to that shown in Figs. 2 to 4 and the only difference therebetween is that the slip ring unit 100 in Fig. 5 also includes two partition plates 9 for partitioning the predetermined space 8 into a plurality of regions. In these embodiments, the gas flow distribution in the predetermined space 8 is adjusted by the partition plates 9, so as to achieve a more uniform cooling effect for the individual slip ring brushes 4. Other embodiments may include different numbers of partition plates 9 and the scope of the present disclosure is not restricted in this regard.

The slip ring unit 100 in accordance with embodiments of the present disclosure may be applied in an electric machine, such as electromotor or electric generator.

Various embodiments of the present disclosure have been described above and the above description is only exemplary rather than exhaustive and is not limited to the embodiments of the present disclosure. Many modifications and alterations, without deviating from the scope and spirit of the explained various embodiments, are obvious for those skilled in the art. The selection of terms in the text aims to best explain principles and actual applications of each embodiment and improvements of technology in the market made by each embodiment, or enable other ordinary skilled in the art to understand embodiments of the present disclosure.

Claims

A slip ring unit (100) , comprising:

a slip ring box (2) comprising a gas inlet (21) and a gas outlet (22) ;

a slip ring body (3) disposed in the slip ring box (2) ;

a slip ring brush (4) disposed in the slip ring box (2) and being in contact with the slip ring body (3) ; and

a suction device (5) disposed at the gas outlet (22) and configured to draw gas in the slip ring box (2) via the gas outlet (22) , such that cooling gas enters the slip ring box (2) via the gas inlet (21) .
The slip ring unit (100) of claim 1, wherein the suction device (5) includes:

a fan (51) configured to draw the gas in the slip ring box (2) when rotating; and

a cover (52) covering the fan (51) and the gas outlet (22) and comprising an exhaust port (53) for discharging the gas drawn from the slip ring box (2) by the fan (51) to an external environment.
The slip ring unit (100) of claim 2, wherein the fan (51) and the slip ring body (3) are mounted on a same rotary shaft (6) .
The slip ring unit (100) of claim 1, further comprising:

a baffle (7) disposed in the slip ring box (2) between the gas inlet (21) and the slip ring brush (4) , wherein a predetermined space (8) in communication with the gas inlet (21) is formed between the baffle (7) and an inner wall of the slip ring box (2) , and the baffle (7) is provided thereon with a plurality of openings (71) facing towards the slip ring brush (4) .
The slip ring unit (100) of claim 4, wherein a gas guide (72) is disposed at an edge (710) of at least one opening (71) of the plurality of openings (71) , the gas guide (72) being configured to guide the cooling gas towards the slip ring brush (4) .
The slip ring unit (100) of claim 5, wherein the gas guide (72) is disposed at a position on the edge (710) of the at least one opening (71) close to the suction device (5) and is tilted towards a direction away from the suction device (5) with respect to the baffle (7) .
The slip ring unit (100) of claim 6, wherein each of the plurality of openings (71) is rectangular and the gas guide (72) tilting towards an interior of each opening is disposed at two adjacent sides of each opening (71) close to the suction device (5) .
The slip ring unit (100) of claim 4, further comprising at least one partition plate (9) for partitioning the predetermined space (8) into a plurality of regions.
The slip ring unit (100) of claim 1, wherein the slip ring brush (4) is a carbon brush.
An electric machine comprising a slip ring unit (100) according to any of claims 1 to 9.